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Date: Tue, 18 Jun 2013 01:10:58 -0700 From: Eric Dumazet <eric.dumazet@...il.com> To: Dmitry Kravkov <dmitry@...adcom.com> Cc: davem@...emloft.net, netdev@...r.kernel.org, eilong@...adcom.com Subject: Re: [PATCH net-next 1/2] bnx2x: add support for ndo_ll_poll On Tue, 2013-06-18 at 10:42 +0300, Dmitry Kravkov wrote: > Adds ndo_ll_poll method and locking for FPs between LL and the napi. > > When receiving a packet we use skb_mark_ll to record the napi it came from. > Add each napi to the napi_hash right after netif_napi_add(). > > Signed-off-by: Dmitry Kravkov <dmitry@...adcom.com> > Signed-off-by: Eilon Greenstein <eilong@...adcom.com> > --- > drivers/net/ethernet/broadcom/bnx2x/bnx2x.h | 125 +++++++++++++++++++++++ > drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 73 +++++++++++-- > drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.h | 23 ++++- > drivers/net/ethernet/broadcom/bnx2x/bnx2x_main.c | 4 + > 4 files changed, 213 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h > index f76597e..a295a53 100644 > --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h > +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x.h > @@ -485,6 +485,21 @@ struct bnx2x_fastpath { > struct bnx2x *bp; /* parent */ > > struct napi_struct napi; > + > +#ifdef CONFIG_NET_LL_RX_POLL > + unsigned int state; > +#define BNX2X_FP_STATE_IDLE 0 > +#define BNX2X_FP_STATE_NAPI (1 << 0) /* NAPI owns this FP */ > +#define BNX2X_FP_STATE_POLL (1 << 1) /* poll owns this FP */ > +#define BNX2X_FP_STATE_NAPI_YIELD (1 << 2) /* NAPI yielded this FP */ > +#define BNX2X_FP_STATE_POLL_YIELD (1 << 3) /* poll yielded this FP */ > +#define BNX2X_FP_YIELD (BNX2X_FP_STATE_NAPI_YIELD | BNX2X_FP_STATE_POLL_YIELD) > +#define BNX2X_FP_LOCKED (BNX2X_FP_STATE_NAPI | BNX2X_FP_STATE_POLL) > +#define BNX2X_FP_USER_PEND (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_POLL_YIELD) > + /* protect state */ > + spinlock_t lock; > +#endif /* CONFIG_NET_LL_RX_POLL */ > + > union host_hc_status_block status_blk; > /* chip independent shortcuts into sb structure */ > __le16 *sb_index_values; > @@ -557,6 +572,116 @@ struct bnx2x_fastpath { > #define bnx2x_fp_stats(bp, fp) (&((bp)->fp_stats[(fp)->index])) > #define bnx2x_fp_qstats(bp, fp) (&((bp)->fp_stats[(fp)->index].eth_q_stats)) > > +#ifdef CONFIG_NET_LL_RX_POLL > +static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp) > +{ > + spin_lock_init(&fp->lock); > + fp->state = BNX2X_FP_STATE_IDLE; > +} > + > +/* called from the device poll routine to get ownership of a FP */ > +static inline int bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp) static inline bool ? > +{ > + int rc = true; > + > + spin_lock(&fp->lock); > + if (fp->state & BNX2X_FP_LOCKED) { > + WARN_ON(fp->state & BNX2X_FP_STATE_NAPI); > + fp->state |= BNX2X_FP_STATE_NAPI_YIELD; > + rc = false; > + } else { > + /* we don't care if someone yielded */ > + fp->state = BNX2X_FP_STATE_NAPI; > + } > + spin_unlock(&fp->lock); > + return rc; > +} > + > +/* returns true is someone tried to get the FP while napi had it */ > +static inline int bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp) bool > +{ > + int rc = false; > + > + spin_lock(&fp->lock); > + WARN_ON(fp->state & > + (BNX2X_FP_STATE_POLL | BNX2X_FP_STATE_NAPI_YIELD)); > + > + if (fp->state & BNX2X_FP_STATE_POLL_YIELD) > + rc = true; > + fp->state = BNX2X_FP_STATE_IDLE; > + spin_unlock(&fp->lock); > + return rc; > +} > + > +/* called from bnx2x_low_latency_poll() */ > +static inline int bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp) bool > +{ > + int rc = true; > + > + spin_lock_bh(&fp->lock); > + if ((fp->state & BNX2X_FP_LOCKED)) { > + fp->state |= BNX2X_FP_STATE_POLL_YIELD; > + rc = false; > + } else { > + /* preserve yield marks */ > + fp->state |= BNX2X_FP_STATE_POLL; > + } > + spin_unlock_bh(&fp->lock); > + return rc; > +} > + > +/* returns true if someone tried to get the FP while it was locked */ > +static inline int bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp) bool > +{ > + int rc = false; > + > + spin_lock_bh(&fp->lock); > + WARN_ON(fp->state & BNX2X_FP_STATE_NAPI); > + > + if (fp->state & BNX2X_FP_STATE_POLL_YIELD) > + rc = true; > + fp->state = BNX2X_FP_STATE_IDLE; > + spin_unlock_bh(&fp->lock); > + return rc; > +} > + > +/* true if a socket is polling, even if it did not get the lock */ > +static inline int bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp) bool > +{ > + WARN_ON(!(fp->state & BNX2X_FP_LOCKED)); > + return fp->state & BNX2X_FP_USER_PEND; > +} > +#else > +static inline void bnx2x_fp_init_lock(struct bnx2x_fastpath *fp) > +{ > +} > + > +static inline bool bnx2x_fp_lock_napi(struct bnx2x_fastpath *fp) > +{ > + return true; > +} > + > +static inline bool bnx2x_fp_unlock_napi(struct bnx2x_fastpath *fp) > +{ > + return false; > +} > + > +static inline bool bnx2x_fp_lock_poll(struct bnx2x_fastpath *fp) > +{ > + return false; > +} > + > +static inline bool bnx2x_fp_unlock_poll(struct bnx2x_fastpath *fp) > +{ > + return false; > +} > + > +static inline bool bnx2x_fp_ll_polling(struct bnx2x_fastpath *fp) > +{ > + return false; > +} > +#endif /* CONFIG_NET_LL_RX_POLL */ > + > /* Use 2500 as a mini-jumbo MTU for FCoE */ > #define BNX2X_FCOE_MINI_JUMBO_MTU 2500 > > diff --git a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c > index 4e42bdd..d8d371b 100644 > --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c > +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c > @@ -24,6 +24,7 @@ > #include <net/tcp.h> > #include <net/ipv6.h> > #include <net/ip6_checksum.h> > +#include <net/ll_poll.h> > #include <linux/prefetch.h> > #include "bnx2x_cmn.h" > #include "bnx2x_init.h" > @@ -669,7 +670,12 @@ static void bnx2x_gro_receive(struct bnx2x *bp, struct bnx2x_fastpath *fp, > } > } > #endif > - napi_gro_receive(&fp->napi, skb); > + skb_mark_ll(skb, &fp->napi); > + > + if (bnx2x_fp_ll_polling(fp)) > + netif_receive_skb(skb); > + else > + napi_gro_receive(&fp->napi, skb); > } > This is racy [1], so I would not care and always call napi_gro_receive() [1] We would have to flush GRO state every time we call bnx2x_fp_lock_poll() Ideally, we could keep a counter of enabled LLS sockets, to automatically switch off/on GRO, but in net/core, not in every driver. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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